If the producer is ready to produce one/more values prior to the Observer's being ready to consume them, do those values go into a queue?

If there is more than one Observer of the same AsyncObservable, is there a separate queue for each of them?

I'm thinking of AsyncSink[1] used by AsyncIterableX[2] (both of IxJS[3]) and how they might be conceptually related to implementations of AsyncObservable.

[1] https://github.com/ReactiveX/IxJS/blob/master/src/asyncsink....

[2] https://github.com/ReactiveX/IxJS/blob/master/src/asyncitera...

[3] https://github.com/ReactiveX/IxJS